This invention relates to microstrip antenna radiators.
A microstrip antenna radiator may be defined in general terms as one or more lengths of conductor strip which form(s) the radiating element(s) separated from yet parallel to a ground plane, the element(s) being fed from one end with microwave energy. Two forms of radiator are
(a) a single element (end radiator), and
(b) a so-called "comb" antenna in which a central feed conductor has on one side a plurality of right-angled half-wave side branches spaced at one wavelength intervals. A modification of the basic comb antenna has branches on both sides, the two sets of branches being staggered by one half-wavelength.
All discontinuities in microstrip radiate, either by intention or spuriously. Such elements as corners, T-junctions, open or closed circuits, as may occur in matching or phase-shifting networks, are encountered in antenna feed systems, and their unintended radiation will set a limit to the accuracy with which design radiation patterns can be achieved.